<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>尺寸</title>
    <style>
        body{
            height: 300px;
        }
        .container{
            /* 像素 */
            /* width: 100px;
            height: 100px; */
            width: 80%;
            height: 50%;
        }

        span{
            width: 200px;
            height: 100px;
        }
    </style>
</head>
<body>
    <div class="container">div
        <div class="container">div1</div>
    </div>


    <span>span1</span>

</body>
</html>